Ground plane

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In electrical engineering, a ground plane is an electrically conductive surface.

1 Radio antenna theory
2 Printed circuit boards
3 See also
4 External articles

[edit] Radio antenna theory

In telecommunication, a ground plane structure or relationships exists between the antenna and another object, where the only structure of the object is a structure which permits the antenna to function as such (e.g., forms a reflector or director for an antenna). This sometimes serves as the near-field reflection point for an antenna, or as a reference ground in a circuit.

There are a variety of ground planes, including drooping ground planes, and flat circular ground plane antennas. A ground plane may consist of a natural surface, such as the Earth (or ocean) or an artificial surface of opportunity (such as the roof of a motor vehicle). A ground plane can also be a specially designed artificial surface (such as the radial elements of a quarter-wave ground plane antenna). Artificial (or substitute) grounds (e.g., ground planes) concerns the grounding structure for the antenna and includes the conductive structure used in place of the earth and which grounding structure is distinct from the earth.

[edit] Printed circuit boards

A ground plane in PCB assembly is a layer of copper that appears to most signals as an infinite ground potential. This helps reduce noise and helps ensure that all integrated circuits within a system compare different signals' voltages to the same potential.

It also serves to make the circuit design easier, allowing the designer to ground anything without having to run multiple tracks; the component needing grounding is routed directly to the ground plane on another layer.

Ground planes can also be placed on adjacent layers to power planes creating a large parallel plate capacitor that helps filter the power supply.

Ground planes are sometimes split and then connected by a thin trace. This allows the separation of analog and digital sections of a board or the inputs and outputs of amplifiers. The thin trace is low enough impedance to keep the two sides very close to the same potential while keeping the ground currents of one side from impacting the other.